Source of disease agent
The person, animal, or inanimate object (water, soil) from which an infectious agent passes or is disseminated to a hostInternet Def: The source of infection is defined as "the person, animal, object or substance from which an infectious agent passes or is disseminated to the host (immediate source).
Reservoir of a disease agent
+Any person, animal, anthropod, soil, plant or substance in which an infectious agent lives and multiplies; on which it primarily depends for survival; and where it reproduces itself in such manner that it can be transmitted to a susceptible host +Can be a living organism or nonliving sites (soil and water) + Typically harbors the agent without injury to itself and can serve as a source from which other individuals can be infectedInternet Def: The reservoir is defined as any person, animal, arthropod, plant, soil, or substance, or a combination of these, in which an infectious agent normally lives and multiplies, on which it depends primarily for survival, and where it reproduces itself in such a manner that it can be transmitted to a susceptible host.
Carrier of Disease Agent
A person or organism that harbors an infectious agent capable of transmitting the disease to others. The carrier may or may not show signs/symptoms of the disease.
Life Cycle of Infection
Infectious Agent>>Reservoir>>Portal of Exit>>Mode of Transmission>>Portal of Entry>>Susceptible Host
Mode of Infectious Disease Transmission
Direct contactIndirect contact
Direct Contact Transmission
By direct or immediate transfer of the agent to an appropriate portal of entry by personal contact (eg, touching, biting, kissing, sexual intercourse, coughing)Requires close association between infected person and susceptible host and also includes droplet spread
Indirect Types of Transmission
(a) Vehicleborne transmit an infectious agent include food, water, biologic products (blood), and (inanimate objects such as handkerchiefs, bedding, doorknobs, or surgical scalpels) known scientifically as fomites(b) Vectorborne usually involves insects or arthropodsDetails from Internet on (b) above: "Examples of mechanical [vectorborne] transmission are flies carrying Shigella on their appendages and fleas carrying Yersinia pestis, the causative agent of plague, in their gut. In contrast, in biologic [also vectorborne] transmission, the causative agent of malaria or guinea worm disease undergoes maturation in an intermediate host before it can be transmitted to humans
Emerging Infectious Diseases
Diseases that have not occurred in humans before; have occurred previously, but infected only small numbers of people in isolated places; or have occurred throughout human history, but have recently been recognized as diseases due to an infectious agent
Re-emerging Infectious Diseases
Diseases that have gone to such low levels that they were no longer considered public health problems and which are now showing upward incidence or prevalence globally
(a) Mostly occurs in places where there is unsafe water, inadequate sanitation, and poor hygiene(b) The cholera baterium can live in brackish water (slightly salty, as is the mixture of river water and seawater in estuaries) and coastal waters(c) The cholera bacteria thrive in warm weather(d) The Cholera is often mild and without symptoms, but can sometime be severe.
Cholera Facts USA
(a) Was prevelant in the USA in the 1800s(b) It was eliminated due to access to modern water ans sewage treatment systems(c) Travelers sometimes bring contaminated seafood back to the US
First, 1817-1824 Originater in the Ganges River Delta and ended up in an outbreak in Calcutta in 1817Second, 1829-1848 [From Internet: Russia, Hungary, Germany]Third, 1852-1860 Considered most deadly- Hit Asia, Europe, North America, Africa with high fatality rates in 1852Fourth, 1863-1875Fifth, 1881-1896Sixth, 1899-1923Seventh, 1961-Present Spread throughout Asia and the Middle East until it reached Africa in 1971
(a) The bacteria is found in the feces of infected individuals (b) Leakages in the sewage system may contaminate the clean, potable water, making it unfit for drinking and use(c) This bacteria can be transferred onto food via dirty hands (d) Contaminated food or water serves as a means for transmitting the disease from one person to another
Concept of STI
(a)An infection that can be transferred from one person to another through oral-genital contact, the use of sexual toys, kissing, or sexual intercourse.(b)Are dangerous because they spread easily and cannot be detected by just looking at a person(c) People with STIs usually do not have symptoms(d) Most are transmitted through vaginal, anal, or oral sex. Some can be transmitted non-sexually, like from mother-to-child during pregnancy or breastfeeding.
Concept of STD
Infection that is passed from one person to another during sexual contact for which their are symptoms and consequential impairment or abnormalities(a) shows on the body or is discovered by a doctor during assessment(b) while all STDs begin with STIs not all STIs are STDs
STI causal agents
1. Bacteria- (STI caused) Chlamydia, Gonorrhea, Syphilis2. Virus-(STI caused) HIV/AIDS, Human Papilloma Virus,Hepatitis B, Herpes 3. Parasite- (STI caused) Trichomoniasis
-The word "Malaria" is derived from the Italian word, "Mal'aria" meaning "bad air" associated with swamps and marshes-In 1898, the Italian zoologist, Giovanni Battista Grassi, discovered that malaria was transmitted by mosquitoes-Malaria is a vector borne disease of the liver and the red blood cells-The female Anopheles mosquito is the vector and host-Humans are also hosts-The disease can be acute or chronic-Malaria has been eliminated from almost all of Europe and large parts of Central and South America
Plasmodium Parasite Species
-Malaria parasitesbelong to the plasmodium species/family-There are over 100 plasmodium species, which can infect, birds, monkeys, and humans-Four of the plasmodium parasite species affect humans:falciparum (Slide 12)vivax (Slide 13)ovale (Slide 14)malariae (Slide 15)-One of the plasmodium species affectsmonkeys and humans is called knowlesi (Slide 16)
What is TB?
-one of the world's deadliest diseases -Bacteria: Mycobacterium tuberculosis -TB usually affects the lungs (pulmonarytuberculosis), but can also affect:Ø BonesØ BrainØ KidneysØ Lymph NodesØ Spine
What happens when a person is exposed to TB?
-May develop active TB .(symptomatic and contagious)qTB may remain latent-Latent TB may become active TB ifthe immune system grows weaker-A person exposed to TB may never get active disease
How do TB germs spread?
TB spreads from person to person through the air by:-coughing-sneezing-singing-talking
Who is at risk for TB?
-HIV-Children £ 5 years with apositive TST-Underweight or malnourished-Substance abusers (smoking,alcohol, injection drug use)-TNF-α antagonists forrheumatoid arthritis or Crohn'sdisease-Medical conditions ( DM, CRFor on hemodialysis, cancer..Etc....-Incarcerated population
Source of Surveillance Data
=-vital records-directly from the persons in a population-laboratory, hospitals, doctors offices, insurance Companies-Surveys-environmental monitoring systems-animal Health data-Census data
Types of surveillance
=-active surveillance-passive surveillance-Syndromic surveillance-Sentinel surveillance
=-initiated by state/Local Health departments-active surveillance involves:a. visiting Health facilitiesb. talking to Health-care providers and reviewing medical recordsc. physical review of medical records and registers-expensive-used for limited period of time-Achieves more complete and accurate reporting than passive surveillance
-Regular reporting of disease data by all institutions-There is no active search for cases.-Relies on the cooperation of health-care providers —laboratories, hospitals, health facilities and private practitioners-involves the regular collection and reporting of surveillance data-Commonest method used to detect vaccine-preventable diseases-less expensive than other surveillance strategies-Diseases are reported by healthcare providers-Covers wide areas (whole country or state/provinces)-because it relies on an extensive network of health workers, it can be difficult to ensure completeness and timeliness of data
=-is used when high-quality data are needed about a particular disease that cannot be obtained through a passive system-data Collected in a well-designed Sentinel system-data Collected in selected Health facility (usually a general or infectious disease hospital) that serves large pop.-facility should be willing to participate-it has medical staff sufficiently specialized to diagnose, treat and Report cases of the disease under surveillance-it has a high-quality diagnostic laboratory-can be active or passive
=-focuses on one or more symptoms rather than a physician-diagnosed or laboratory-cOnfirmed disease-Constellation of signs and symptoms grouped into categories-Uses less Specific criteria. more LIKELY to identify persons without the disease of interest-provides AN earlier indication of AN unusual increase in illnesses than traditional surveillance
Why is surveillance important?
=-detection of emergence of disease pattern-detection of outbreak/epidemic-Resource allocation/setting priorities/planning-program Development and Implementation-evaluating Control and prevention activities-detection of changes in Health practice-detection of Demographic changes-Estimates of a Health problem-natural history of disease-prevention and intervention-hypothesis testing
Prerequisites for health
=-peace-Shelter-education-food-Income-stable eco-system-sustainable resources-social Justice/equality
Health promotion action
-Build healthy public policy-Create supportive environments-Strengthen community actions-Develop personal skills-Reorient health servicesExample of Zika: Slide 20
History of health promotion
-many scholars have accepted health promotion since the 1980's Has its roots in ancient civilization -BC Greeks broke from the concept that the super natural caused disease and developed idea that there was an interrelationship between health and the environment in which we live -aristotle offered the first definition for health promotion "a good life for humans is one in which they function well.
Mandala of Health
Mid-1980's Hancock's model of the human ecosystem; attempt to better understand the determinants of health.
CDC's Field Learning 2014 Ebola Epidemic: 11 Common Domains of Practice
•Campaigns•Communication counsel•Communication planning•Community/stakeholder engagement•Formative assessment•Media relations/public affairs•Measurement and evaluation•Message and materials development•Partner engagement•Risk communication•Training and education